Wear indicating surfacing device



April 5, 1966 B. R. BUZZELL 3,243,925

WEAR INDICATING SURFACING DEVICE Filed July 18, 1963 Fig.

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Benjamin R. Buzze/l 1N VEN TOR.

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United States Patent 3,243,925 WEAR lNDlCATING SURFACENG DEVICE Benjamin R. Buzzeii, 79 Hillcrest Road, Cape Elizabeth, Maine Filed July 18, 1963, Ser. No. 295,967 7 Chums. (Cl. 51-372) This invention relates to a new and useful improvement in polishing devices especially useful in connection with the polishing of such objects as dental castings made of plastics, gold, silver or steel alloys as well as other objects.

In connection with the polishing of small objects such as castings made for dental purposes, abrasive polishing members in the form of felt cones adapted to hold abrasive matter such as pumice are utilized, these polishing cones being readily mounted and rotated by a screw-type chuck onto which the polishing cone is spun. The polishing cone is replaced after it is worn away by a sufiicient amount requiring the exercise of judgment on the part of the operator in this latter regard. Haste and overconcentration on the part of the operator has often in the past resulted in excessive wearing away of the polishing cone so as to expose the hard metallic surfaces of the screw chuck resulting in the marring, marking or disfiguring of the object being polished. It is therefore a primary object of the present invention to avoid the loss of time and material resulting from misjudgment or lack of attention to the hazard resulting from the untimely replacement of the polishing cone threadedly mounted on a rotating screw chuck.

In accordance with the foregoing object, an important object of the present invention is to provide an insert for polishing cones of the aforementioned type which will provide a telltale warning that the polishing cone has been worn away by a suflicient amount requiring replacement before the screw chuck is exposed.

A further object of the present invention is to provide a wear indicating insert for polishing cones of the aforementioned type which is made of a resilient material such as rubber that will not mar the object being polished and will also be of a color readily distinguishable from that of the polishing cone.

An additional object of the present invention is to provide a bullet shaped insert for polishing cones whereby the polishing cone may be threadedly mounted on a screw chuck and completely worn away by a useful amount for polishing purposes without any danger of inadvertent exposure of the screw chuck so as to both eliminate the hazard of marring the object being polished as well as avoiding premature replacement of the polishing cone.

The wear indicating insert of the present invention utilized in connection with polishing cones, also by virtue of its shape and installation represents a practicable and economically feasible safety measure in the use of polishing cones adapted to be mounted on externally threaded types of tapered chucks by means of which such polishing cones are rotated at relatively high speeds for polishing purposes.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective view of the disassembled parts of the polishing device.

FIGURE 2 is a sectional view of the assembled portions of the polishing device mounted on a screw-type chuck.

FIGURES 3 and 4 are sectional views of the polishing device in different stages of wear.

3,243,925 Patented Apr. 5, 1966 FIGURE 5 is a sectional view of the polishing device before being mounted on the screw chuck.

Referring now to the drawings in detail, it will be observed from FIGURES l, 2 and 5, that the polishing device generally referred to by reference numeral '10 includes a polishing cone member 12 adapted to receive a resilient insert 14 mounting the cone member on a screwtype chuck 16 adapted to be rotated at the proper speed by a polishing motor (not shown). The polishing member or cone 12 is made of a felt material as is well known in the art, this material being formed into the cone shape under high pressure. These polishing cones are provided with sockets within which the screw chuck 16 is received. The screw chuck is therefore formed with an externally threaded tapered portion 18 adapted to be spun into the socket portion of the polishing cone up to a predetermined depth so that the cone will thereafter be rotated with the screw chuck. When the external surface of the polishing cone is wetted and pumice applied thereto, it will be effective to polish small objects such as dental castings. These felt cones however, wear away and must be replaced before the hard surface threads of the screw chuck are exposed therethrough. It will there fore be apparent, that the operators judgment in this latter regard is required so as to replace the polishing cone in advance of the exposure of the screw chuck therethrough but not prematurely so that full advantage may be taken of the useful life of the polishing cone.

In order to avoid mis-judgment in the untimely replacement of the polishing cone, the resilient insert 14 is received within the socket portion 28 of the polishing cone 12. The insert 14 is bullet-shaped and provided with a solid forward portion ZZ-and an expandable rear portion 24 having a chuck receiving recess 26 therein as more clearly seen in FZGURE 5. In this manner, the exter nally threaded tapered portion 18 of the screw chuck is threadedly received and will be effective to expand and vedge the portion 24 of the insert within the socket 23 of the polishing cone so as to firmly mount the polishing cone on the screw chuck for rotation therewith. The insert 14 is made of a material such as rub ber which is nonabrasive so as to avoid marring the surface of the object being polished and is also made of a color that is readily distinguishable from the color of the felt material forming the polishing cone. Also as a warning of the impending exposure of the insert 14, a color contrasting dye 28 may be inserted into the socket portion 26 of the polishing cone adjacent to the forward portion 22 of the bullet-shaped insert. An additional measure of safety is thereby provided.

From the foregoing description, the construction, operation and utility of the wear indicating polishing device of the present invention will be apparent. It will therefore be appreciated, that the polishing cone may be utilizeu to its fullest extent without any danger of unintentional exposure of the screw chuck therethrough which could mar the object being polished. Accordingly, when the polishing cone is worn down by its useful amount, particuiarly at the forward portion thereof, the contrasting dye 28 will be initially exposed as shown in FIGURE 3 before exposure of the insert 14 itself as shown in FIGURE 4. The operator will therefore have sufiicient time within which to stop rotation of the screw chuck and replace the polishing cone. The relatively small cost of providing the polishing cones with the wear indicating inserts pursuant to the present invention, will be completely justified because of the elimination of the hazard of exposing the screw chuck through the polishing cone as well as to avoid premature replacement of the polishing cone.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous 7 i 1. In combination with an abrasive carrying polishing member having a socket portion adapted to be mounted on a rotating chuck, wear indicating safety means including; a resilient insert received in said socket portion and mounting the polishing member on the chuck for rotation therewith, and a contrasting dye disposed in the socket portion of the polishing member for exposure when the polishing member is worn down to a predetermined distance from the chuck preceding the exposure of the resilient insert to indicate replacement is needed.

2., In combination with an abrasive carrying polishing member having a socket portion threadedly mounted on a rotating screw chuck, Wear indicating safety meansineluding: a resilient insert received in'said socket portion having a color distinguishable from that of the polishing member and mounting the polishing member on the screw chuck for rotation therewith, whereby the polishing member may be worn down to a predetermined distance from the screw chuck exposing the resilient insert indicating replacement is needed before exposing the screw chuck, and a color contrasting dye disposed in the socket portion of the polishing member adjacent a forward portion of the insert for providing a warning of the impending exposure of the insert.

3. The combination of claim 2, wherein said insert is bullet-shaped and includes a solid forward portion and an expandable rear portion for threaded reception of the screw chuck to wedge the insert within the socket portion of the polishing member.

4. The combination of claim 1, wherein said insert is bullet-shaped and includes a solid forward portion and an expandable rear portion for threaded reception of the chuck to wedge the insert within the socket portion of the polishing member.

5. In combination with a polishing cone made of abra- V sive holding felt for polishing an object and a chuck screw chuck when the polishing cone is worn away by for rotating said polishing cone, wear indicating means comprising, a resilient insert received in said polishing cone for mounting thereof on the chuck, said insert being made of non-abrasive material distinguishable in color from the polishing cone for telltale exposure therethrough before exposure of the chuck when the polishing coneris worn away by a useful amount to avoid marring of the object by the chuck and a color contrasting dye disposed in the socket portion of the polishing cone for providing a warning of the impending exposure of the insert.

6. The combination of claim 5, wherein said insert is bullet-shaped and includes a solid forward portion and an expandable rear portion for threaded recepting' of the screw chuck to wedge the insert within a socket portion of the polishing cone.

7. In combination with a polishing cone made of abrasive holding felt for polishing an object and a screw chuck for rotating said polishing cone, Wear indicating means comprising, a resilient insert received in said polishing cone for threaded mounting thereof on the screw chuck, said insert being made of non-abrasive material distinguishable'in color from the polishing cone for telltale exposure therethrough before exposure of the a useful amount to avoid marring of the object by the screw chuck, said insert being bullet-shaped and includ ing a solid forward portion and an expandable rear portion for threaded reception of the screw chuck to wedge the insert within a socket portion of the polishing cone and a color contrasting dye disposed in the socket por-V tion of the polishing cone adjacent said forward portion of the insert for providing a warning of the impending exposure of the insert.

References Cited by the Examiner V UNITED STATES PATENTS 170,178 11/1875 Locke 51 FOREIGN PATENTS 421,912 9/1933 GreatBritain.

ROBERT C: RIORDON, Primary Examiner. LESTER M. SWINGLE, Examiner. 

1. IN COMBINATION WITH AN ABRASIVE CARRYING POLISHING MEMBER HAVING A SOCKET PORTION ADAPTED TO BE MOUNTED ON A ROTATING CHUCK, WEAR INDICATING SAFETY MEANS INCLUDING; A RESILIENT INSERT RECEIVED IN SAID SOCKET PORTION AND MOUNTING THE POLISHING MEMBER ON THE CHUCK FOR ROTATION THEREWITH, AND A CONTRASTING DYE DISPOSED IN THE SOCKET PORTION OF THE POLISHING MEMBER FOR EXPOSURE WHEN THE POLISHING MEMBER IS WORN DOWN TO A PREDETERMINED DISTANCE FROM THE CHUCK PRECEDING THE EXPOSURE OF THE RESILIENT INSERT TO INDICATE REPLACEMENT IS NEEDED. 